A major goal of this laboratory is the elucidation of neural mechanisms underlying the development of normal behavior and equally to understand the mechanisms responsible for recovery of function and plasticity following central nervous system injuries, particularly those originating in infancy. The approach is broadly multidisciplinary, involving behavioral, anatomical, electrophysiological, endocrinological, pharmacological and biochemical techniques. The experimental subject is the rhesus monkey, which because of its protracted span of postnatal development and its remarkable capacity for restitution of function following cortical lesions of early onset is unsurpassed as a model of normal and disordered human development. The focus of these studies is on the prefrontal granular cortex, a slowly maturing neocortical region of the primate brain particularly appropriate for studies on the sequence, duration, and correlation of structural and functional events in ontogeny. The emphasis of this research is reflected in the titles of the four subprojects; (1) Cryogenic Depression of Cortex and Subcortical Unit Activity at Different Stages of Postnatal Development. (2) Sexual Dimorphism in Cortical Structure and Function. (3) Behavioral and Anatomical Consequences of Prenatally Induced Brain Damage. (4) Neurochemical Correlates of Normal and Disordered Development in Primates. BIBLIOGRAPHIC REFERENCES: Brown, R.M. and Goldman, P.S.: Catecholamines in neocortex of rhesus monkeys: regional distribution and ontogenetic development. Brain Research, 124: 576-580, 1977. Goldman, P.S. and Alexander, G.E.: Maturation of prefrontal cortex in the monkey revealed by local reversible cryogenic depression. Nature 267: 613-615, 1977.